The present invention relates to humidification of hydrocarbons, such as butadiene, prior to catalytic polymerization, and will be described with particular reference thereto. It should be appreciated, however, that the process is also applicable to other fluids in which water is poorly soluble.
The polymerization of 1,3-butadiene to form cis-1,4-polybutadiene with the aid of Ziegler-Natta type catalysts, such as those incorporating aluminum alkyls, alkyl chlorides, or aluminum alkoxides with a transition element, such as cobalt or nickel, is known. The presence of controlled amounts of water in certain transition metal-catalyzed polymerizations, such as the polymerization of butadiene, has been found advantageous for the activation of the catalyst. In particular, small amounts of dissolved water, of the order of 10 to 200 ppm, have been found to be beneficial to the catalytic activity.
Water may be introduced by a dispersion in the reactants themselves, e.g., 1,3-butadiene, or in the solvents such as hexane. In one method, water is passed through a porous frit material into a stream of the hydrocarbon mixture. In other methods, water is introduced to the polymerization reactor. Another method of introducing water employs a cyclone. However, the presence of undissolved water in liquid form in the polymerization reactor has been found to be deleterious to the catalyst, leading to inactivation. Prior methods of incorporating water have often resulted in the presence of water droplets in the hydrocarbon feed.
The present invention provides a new and improved apparatus and method for humidification of a hydrocarbon, which overcomes the above-referenced problems and others.
According to one exemplary embodiment, the invention provides a method of humidifying a hydrocarbon stream wherein the hydrocarbon stream is passed through a bed including a packing material and water, thereby forming a humidified hydrocarbon stream having water dissolved therein.
According to another exemplary embodiment, an apparatus for humidifying a hydrocarbon stream is provided. The apparatus includes a vessel which defines an interior cavity. A bed of a packing material is disposed in the cavity. Water fills at least a portion of the bed. An inlet adjacent a lower end of the cavity receives a hydrocarbon stream.
The present invention can produce a hydrocarbon stream that is humidified without entraining liquid water.
Additionally, the level of water in the hydrocarbon stream may be controlled.